The figure is not drawn to scale. Tank X measuring 55 cm by 45 cm by 19 cm contained 16.95 ℓ of water. Tank Y measuring 40 cm by 25 cm by 33 cm contained 19 ℓ of water. Peter poured some water from Tank X into Tank Y without spilling and the water level of Tank Y rose to 31 cm. What was the height of water level left in Tank X?
1 ℓ = 1000 cm³
19 ℓ = 19000 cm³
16.95 ℓ = 16.95 x 1000 = 16950 cm³

Height of water in Tank Y at first
= 19000 ÷ 40 ÷ 25
= 19 cm

Increase in the height of water in Tank Y
= 31 - 19
= 12 cm

Volume of water poured into Tank Y
= 40 x 25 x 12
= 12000 cm³ 

Volume of water left in Tank X
= 16950 - 12000
= 4950 cm³ 

Height of water left in Tank X
= 4950 ÷ 55 ÷ 45
= 2 cm

Answer(s): 2 cm